Resistance exercise is any exercise where muscles contract against an external resistance, the objective being to increase strength, tone, mass, or muscular endurance. Lifting weights using dumbbells or weight machines is an example of resistance exercise. Resistance can also come from elastic tubing or bands, cinder blocks, one's own body weight (for example, as with conventional push-ups), or any other object that forces one's muscles to contract. Broadly speaking, exercise involving resistance training develops the strength and endurance of large muscle groups.
Conventional push-ups are a time-honored and effective exercise predominantly used to develop upper body strength. They are considered a body weight exercise because it is one's own body weight that provides the resistance. Body weight exercises such as push-ups require the individual to stabilize and balance the weight in order to lift the body. This need for balance requires that numerous muscle groups be incorporated, and therefore push-ups and other body weight exercises provide strengthening beyond just those muscles primarily involved in actually displacing the body weight.
The muscles predominantly involved in traditional push-ups are the arms (particularly the triceps), the shoulders (particularly anterior deltoids) and the chest (pectoralis major and pectoralis minor). Although the chest muscles are one of the primary groups of muscles exercised and strengthened by performing push-ups, the effectiveness of push-ups for strengthening the pectoralis muscles is limited. The arms (triceps) are smaller muscles that move through a larger range of motion during a push-up, and therefore fatigue more quickly. This is a critical limiting factor in the duration and intensity of exercise that the chest muscles endure. Often, the fatigued arm muscles reach the point of failure before the pectoralis muscles, and at this point the push-up exercise is no longer effective.
Typically, pectoralis muscle strengthening and development is achieved through weight-lifting. This frequently requires expensive equipment to isolate and maximize the benefit. Unfortunately the “anytime, anywhere” usefulness of body weight exercise is lost. Bench press, chest butterfly, and cross-over pulls are common weight-lifting exercises that target the pectoralis muscles. To some extent, these exercises (particularly bench press) require significant muscle input from the arms, and therefore suffer from the same fatigue-limiting effect seen with standard push-ups. To overcome this, so-called pec decks were created. To a significant extent, these machines isolate their resistance effects to the chest and overcome the limitation for pectoral exertion associated with arm fatigue. These machines are effective for chest development but are commonly large, heavy, not portable, and expensive.
There are some devices available to enhance the effectiveness and comfort of traditional push-ups; however, a continuing and unmet need exists for new and improved exercise equipment that addresses the foregoing arm-fatigue limitations.